JP4803596B2 - Temperature measuring device - Google Patents

Description

  The present invention relates to a temperature measuring device that measures the temperature of a temperature-measured body arranged in a container.

  In a semiconductor manufacturing process, a semiconductor substrate is heated by a heating mechanism such as a heater built in the mounting table while supplying the processing gas into the processing chamber while the semiconductor substrate is mounted on the mounting table in the processing chamber. Then, a predetermined process is performed on the semiconductor substrate. In such processing, since the heating temperature greatly affects the quality of the semiconductor substrate, it is necessary to accurately measure the temperature of the mounting table (or heating mechanism). For this reason, thermocouples with excellent thermal response are often used for temperature measurement of the mounting table, and in particular, a sheathed thermocouple configured by covering the thermocouple with a sheath made of heat-resistant metal or the like. Are often used (see, for example, Patent Documents 1 and 2).

  The sheath thermocouple is usually attached airtight to the wall of the processing container so that the tip is in contact with the mounting table. However, since the sheath thermocouple is long, an attachment error in the length direction tends to occur. In addition, when the processing gas is supplied into the processing container, the mounting table moves somewhat due to a pressure change in the processing container, and therefore the distal end portion of the sheath thermocouple is likely to be in a non-contact state with the mounting table. If the tip is not in contact with the mounting table, the temperature of the mounting table cannot be measured accurately. For this reason, the sheath thermocouple absorbs attachment errors and can follow the movement of the mounting table, so that the sheath thermocouple has a degree of freedom in the advancing and retreating direction relative to the mounting table, that is, in the length direction. Preferably it is attached.

  Therefore, as shown in FIG. 6, one end and the other end of the bellows C that are slightly expanded and contracted, here, are attached to the sheath thermocouple A and the wall of the processing vessel, for example, the bottom wall D, respectively. Thus, the sheath thermocouple A is pressed weakly against the mounting table B in advance, and the sheath thermocouple A follows the movement of the mounting table by the expansion and contraction of the bellows C.

  However, in the semiconductor manufacturing process, in general, the inside of the processing container is reduced to, for example, a vacuum pressure when the processing gas is supplied. In addition, since the sheath thermocouple is attached using the bellows C described above because of having a certain diameter R, the atmosphere corresponding to the diameter R is reduced in the bellows C by, for example, reducing the inside of the processing container to a vacuum pressure. A pressure difference from the vacuum is applied, and a significantly large pressing force (see arrow E in FIG. 6) against the mounting table B acts on the sheath thermocouple A. As a result, the sheath thermocouple A is strongly pressed against the mounting table B, and the sheath thermocouple A or the mounting table B may be damaged.

  In order to avoid such a situation, the sheath thermocouple and the wall of the processing vessel are sealed with a rigid sealing member without using a bellows, and a part of the metal sheath of the sheath thermocouple is peeled off. In addition, by exposing a part of a thermocouple wire coated with a resin coating such as Teflon (registered trademark) to be loosened, the sheath thermocouple has a degree of freedom in the advancing / retreating direction with respect to the mounting table, and It is also conceivable that the tip of the sheath thermocouple is urged by a spring in the direction of pressing against the mounting table. However, in such an embodiment, since the resin-coated thermocouple wire is exposed to the atmosphere in the processing container, when the processing gas is a corrosive gas such as a halogen-based gas, the resin is corroded by the corrosive gas. There is also a concern of organic contamination.

  The present invention has been made in view of such circumstances, a temperature measuring device using a sheath thermocouple, while preventing damage to the sheath thermocouple or the temperature-measured body due to decompression in the container, It is an object of the present invention to provide a temperature measuring device capable of accurately measuring the temperature of a temperature measuring object.

The present invention is also a temperature measuring device using a sheathed thermocouple, and accurately controls the temperature of the temperature-measured body while preventing damage to the sheath thermocouple or the temperature-measured body due to the reduced pressure in the container. An object of the present invention is to provide a temperature measuring device capable of preventing corrosion caused by the corrosive gas in the container in addition to the measurement.
JP-A-4-63281 JP-A-6-176855

  In order to solve the above-described problem, according to a first aspect of the present invention, there is provided a temperature measuring device for measuring the temperature of a temperature-measured body arranged in a container, wherein a thermocouple element is covered with a sheath. A tip portion that is positioned in the container and is movable following the temperature-measured body; and a buffer portion that is provided so as to extend outside the container and allows the tip portion to move. A sheath thermocouple, a spring member that urges the distal end of the sheath thermocouple in a direction to press the temperature-measured body, the spring member, and the buffer portion, and the inside of the container A sealing member provided in close contact with the wall portion of the container so as to communicate with the inside, and an end portion of the buffer portion extending to the outside, and an end portion of the buffer portion of the sealing member extending to the outside With joints formed hermetically by welding or brazing Providing a temperature measuring device according to claim Rukoto.

  According to a second aspect of the present invention, there is provided a temperature measuring device for measuring the temperature of a temperature-measured body arranged in a container having a corrosive gas atmosphere, wherein the thermocouple element has a corrosion resistance against the corrosive gas. Having a structure covered with a sheath made of a material having, a tip positioned within the container and movable following the temperature-measured body, provided to extend out of the container, A sheath thermocouple having a buffer portion that allows movement of the tip portion, and a material that urges the tip portion of the sheath thermocouple in a direction in which the tip portion is pressed against the temperature-measured body, and that is resistant to the corrosive gas. A spring member, and the spring member and the buffer portion are accommodated and provided in close contact with the wall portion of the container so that the inside thereof communicates with the interior of the container, and the end portion of the buffer portion is externally provided. Extends and has corrosion resistance to the corrosive gas A temperature measuring device comprising: a sealing member made of a material; and a joint portion formed by welding or brazing on a portion where the end portion of the buffer portion of the sealing member extends to the outside. provide.

  In the second aspect of the present invention, the spring member is a coil spring, and the sealing member moves against the corrosive gas that moves in the advancing and retracting direction with respect to the temperature-measured body as the coil spring expands and contracts. A piston made of a material having corrosion resistance is accommodated, and the sheath thermocouple can be fixed to the piston.

  Furthermore, in the above second aspect of the present invention, when the corrosive gas is a gas containing halogen, the material having corrosion resistance to the corrosive gas is preferably nickel (Ni) or a nickel alloy.

  In the present invention described above, the spring member is preferably made of Inconel (registered trademark).

  Furthermore, in the above-mentioned this invention, it is preferable that the said buffer part is bent so that it can expand-contract to the said to-be-measured body in the advancing / retreating direction. In this case, it is more preferable that the buffer portion is bent in a spiral shape or a waveform.

  According to the first aspect of the present invention, the sheath thermocouple is provided in the container so that the sheath thermocouple is positioned in the container and is movable following the temperature measurement object, and extends outside the container. A bellows that is greatly influenced by the pressure difference between the inside and outside of the container is used because the spring member that urges the tip of the sheath thermocouple in the direction to press the temperature-measured body is provided. Without this, the distal end portion of the sheath thermocouple can be reliably brought into contact with the temperature object. Therefore, it is possible to accurately measure the temperature of the temperature-measured body while preventing the sheath thermocouple or the temperature-measured body from being damaged due to the reduced pressure in the container.

  In addition, according to the second aspect of the present invention, the sheath thermocouple is provided so as to be positioned inside the container and movable following the temperature object, and to extend outside the container. The bellows is composed of a buffer part that allows movement of the tip part, and is provided with a spring member that urges the tip part of the sheath thermocouple in a direction to press the temperature-measured body, so that the bellows is greatly affected by the pressure difference between the inside and outside of the container The tip of the sheath thermocouple can be reliably brought into contact with the temperature-measured body without using or removing a part of the sheath that causes a decrease in corrosion resistance. Moreover, the sheath, the sealing member, and the spring member that are exposed to the atmosphere of the corrosive gas in the container are all formed of a corrosion-resistant material against the corrosive gas, and the joint between the sealing member and the sheath is formed by welding or brazing. Corrosion due to corrosive gas can be prevented. Accordingly, it is possible to accurately measure the temperature of the temperature-measured body while preventing the sheath thermocouple or the temperature-measured body from being damaged due to the decompression in the container and the corrosion due to the corrosive gas in the container. .

Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view schematically showing a wafer processing apparatus provided with a temperature measuring device as one embodiment according to the present invention.

  The wafer processing apparatus 100 includes a chamber 1 as a processing container capable of storing a wafer W, which is a semiconductor substrate, and a temperature control unit that places the wafer W stored in the chamber 1 and adjusts the temperature of the wafer W. As a susceptor 4, a temperature measuring device 5 for measuring the temperature of the susceptor 4 (temperature object), and a process for supplying a processing gas containing a corrosive gas for performing a predetermined process to the wafer W into the chamber 1. A gas supply mechanism 2 and a decompression mechanism 3 capable of decompressing the inside of the chamber 1 are provided.

  The chamber 1 is formed in a substantially cylindrical shape with an open top, and a loading / unloading port 13 for loading / unloading the wafer W is formed on the side wall of the chamber 1 and a gate for opening / closing the loading / unloading port 13. A valve 14 is provided. The susceptor 4 is provided on the bottom wall 19 of the chamber 1 via a column member 11 extending in the height direction, and a heater 40 is embedded therein, and the heater 40 is connected to a heater power supply 41. The heater power supply 41, that is, the heater 40, is controlled by a controller 90 described later based on the measured temperature of the temperature measuring device 5, thereby adjusting the temperature of the wafer W placed on the susceptor 4. Has been.

  A shower head 15 is provided on the upper portion of the chamber 1 so as to close the opening and to face the susceptor 4. The shower head 15 has a diffusion space 16 for diffusing the processing gas by the processing gas supply mechanism 2 inside, and a plurality or a plurality of discharges for discharging the processing gas by the processing gas supply mechanism 2 on the surface facing the susceptor 4. A hole 17 is formed.

  An exhaust port 18 is formed in the lower part of the side wall of the chamber 1. The decompression mechanism 3 includes an exhaust pipe 31 connected to the exhaust port 18 and an exhaust device 32 that exhausts the inside of the chamber 1 through the exhaust pipe 31.

  The processing gas supply mechanism 2 includes a processing gas storage unit 21 storing a processing gas containing a corrosive gas such as a halogen-based gas (a gas containing halogen), and diffusion of the processing gas from the processing gas storage unit 21 into the shower head 15. A conduit 22 led into the space 16, and a mass flow controller 23 and a valve 24 as a flow rate adjusting mechanism for adjusting the flow rate of the processing gas flowing through the conduit 22 are provided. In addition, when supplying several types of different process gas in the chamber 1, the several process gas supply mechanism 2 is provided, for example.

Next, the temperature measuring device 5 will be described in detail.
FIG. 2 is a cross-sectional view of the temperature measuring device 5.

  The temperature measuring device 5 is provided such that a tip portion (one axial end portion) 50a is positioned in the chamber 1 and is movable following the susceptor 4, and on the rear side (the other axial side) of the tip portion, A sheath thermocouple 50 provided so that the buffer portion 50b that allows the movement of the tip portion extends out of the chamber 1 and a spring member that biases the tip portion 50a of the sheath thermocouple 50 in the direction of pressing the susceptor 4 The compression coil spring 53, and the compression coil spring 53 and the buffer portion 50b are accommodated and provided in close contact with the wall portion of the chamber 1, for example, the bottom wall 19, so that the inside thereof communicates with the inside of the chamber 1. The end portion of the buffer portion 50b is extended to the outside, and the end portion of the buffer portion 50b of the seal member 51 is hermetically formed in the portion extending to the outside (atmosphere side outside the chamber 1). And a joint portion 55.

  The sheath thermocouple 50 includes a thermocouple element, a hollow sheath that covers the thermocouple element, and an insulating material such as magnesia that is emphasized in the sheath. The sheath 50 is made of a material having corrosion resistance to a halogen-based gas, for example, pure nickel (Ni), nickel-chromium-molybdenum (NiCrMo), or a nickel alloy such as Hastelloy. Note that the sheath and the insulating material are not necessarily provided in the portion extending to the outside.

  The distal end portion 50 a of the sheath thermocouple 50 is in contact with the susceptor 4 by being inserted into an insertion hole 4 a formed on the lower surface of the susceptor 4, for example. The buffer portion 50b of the sheath thermocouple 50 is bent or curved, for example, spirally so that it can expand and contract in the advancing and retracting direction with respect to the susceptor 4. The end portion of the sheath thermocouple 50 is connected to the signal transmission unit 52, and the signal transmission unit 52 transmits a measurement temperature signal from the sheath thermocouple 50 to a controller 90 described later, and the controller is based on the measurement temperature signal. 90 is configured to control the temperature of the heater power supply 41, that is, the heater 40.

  The sealing member 51 is formed in a cylindrical shape made of a material having corrosion resistance against a halogen-based gas, for example, pure nickel or a nickel alloy, which is the same kind of metal as the sheath of the sheath thermocouple 50, and extends from one side in the axial direction to the other side. In order, the compression coil spring 53 and the cylinder portion 51b that houses the piston 54 that can move in the forward and backward direction with respect to the susceptor 4 as the compression coil spring 53 expands and contracts, and the buffer housing portion that houses the buffer portion 50b of the sheath thermocouple 50 51c. A flange 51 a is formed at one end of the sealing member 51 in the axial direction. The sealing member 51 has one end surface of the flange 51 a attached to the outer surface (bottom surface) of the bottom wall 19 of the chamber 1 in an airtight manner. The aforementioned joint portion 55 is provided on the wall portion at the other axial end of the sealing member 51, and the joint portion 55 is formed by welding or brazing. Here, when the sealing member 51 is made of the same kind of metal as the sheath of the sheath thermocouple 50, both of them can be welded or brazed well, and can be reliably fixed to the sheath by the joint portion 55.

  The compression coil spring 53 is formed of a material that has corrosion resistance to the halogen-based gas and has an elastic force, such as SUS316L including Inconel (registered trademark), nickel, and molybdenum, and the piston 54 is resistant to the halogen-based gas. It is formed of a material having corrosion resistance, for example, pure nickel or a nickel alloy which is the same kind of metal as the sheath of the sheath thermocouple 50. The piston 54 is provided with a through-hole through which the sheath of the sheath thermocouple 50 penetrates, and both of these are fixed by welding, brazing, caulking, or the like. The portion 50a is biased so as to be pressed against the susceptor 4 by the elastic force of the compression coil spring 53 via the piston 54 (in the direction of arrow F). Here, when the piston 54 is made of the same kind of metal as the sheath of the sheath thermocouple 50, the welding or brazing of both is improved, and the piston 54 can be securely fixed to the sheath.

  Each component of the wafer processing apparatus 100 is connected to and controlled by a controller 90 (control unit) having a microprocessor (computer). The controller 90 includes a user interface including a keyboard that performs command input operations and the like to manage each component of the wafer processing apparatus 100, a display that visualizes and displays the operating status of the wafer processing system 1, and the wafer. A control program for realizing processing executed by the processing apparatus 100 under the control of the controller 90 and a storage unit storing a recipe in which processing condition data is recorded are connected. By calling an arbitrary recipe from the storage unit according to an instruction from the interface or the like and causing the controller 90 to execute it, desired processing in the wafer processing apparatus 100 is performed under the control of the controller 90.

  In the wafer processing apparatus 100 configured as described above, the wafer W is processed as follows. First, in a state where the loading / unloading port 13 is opened by the gate valve 14, the wafer W is loaded into the chamber 1 from the loading / unloading port 13 and placed on the susceptor 4, and the loading / unloading port 13 is closed by the gate valve 14.

  Next, the exhaust device 32 of the depressurization mechanism 3 is operated to depressurize the chamber 1 to a predetermined pressure, for example, a vacuum pressure, and the process gas supply mechanism 2 causes the process gas to enter the chamber 1 via the shower head 15. The wafer W is heated by the heater 40 via the susceptor 4 while supplying the flow rate of. When heating by the heater 40, as described above, the sheath thermocouple 50 measures the temperature of the susceptor 4, and the signal transmission unit 52 transmits the measurement temperature signal of the susceptor 4 by the sheath thermocouple 50 to the controller 90. The controller 90 controls the temperature of the heater 40 based on the measured temperature signal, so that the wafer W on the susceptor 4 is adjusted to a predetermined temperature. Thereby, a predetermined process is performed on the wafer W.

  Here, when the processing gas is supplied into the chamber 1 by the processing gas supply mechanism 2 and / or the pressure in the chamber 1 is reduced by the pressure reducing mechanism 3, the pressure in the chamber 1 changes, and the susceptor 4 is shaken. However, the distal end portion 50a of the sheath thermocouple 50 is biased so that the buffer portion 50b expands and contracts in the advancing / retreating direction with respect to the susceptor 4 and is pressed against the susceptor 4 by the compression coil spring 53. Therefore, the susceptor 4 is moved following the movement of the susceptor 4 so that the contact with the susceptor 4 is maintained. Therefore, it is possible to accurately measure the temperature of the susceptor 4, and thereby it is possible to precisely control the temperature of the heater 40 and increase the processed product of the wafer W.

  Further, the spring member, for example, the compression coil spring 53, is biased so as to press the distal end portion 50a of the sheath thermocouple 50 against the susceptor 4, so that a remarkably large pressing force is generated by the pressure difference between the atmosphere and the vacuum as in the prior art. Since it is not necessary to use a bellows that acts, it is possible to prevent the sheath thermocouple 50 from being strongly pressed against the susceptor 4 due to the reduced pressure in the chamber 1, thereby damaging the sheath thermocouple 50 and the susceptor 4. And the durability of the apparatus can be increased.

  In addition, since the sheath thermocouple 50 is bent together with the sheath, for example, in a spiral shape to form the buffer portion 50b, it is not necessary to peel off a part of the sheath and expose the thermocouple element as in the conventional case. Therefore, it is possible to cope with the case where the inside of the chamber 1 is kept at a high temperature.

  In addition, it is preferable that the buffer part 50b has a curvature as small as possible so that the load at the time of expansion / contraction is reduced, and is constant in the advancing / retreating direction with respect to the susceptor 4 so that the load at the time of expansion / contraction is distributed. A shape having regularity is preferred. Examples of such a shape include a waveform as shown in FIG. 3 in addition to the spiral shape shown in FIG.

  Further, each member of the temperature measuring device 5 exposed to a processing gas in the chamber 1, for example, a corrosive gas atmosphere such as a halogen-based gas, that is, the sheath of the sheath thermocouple 50, the sealing member 51, the compression coil spring 53 and the piston 54. Are formed of a material having corrosion resistance to the processing gas, for example, nickel or a nickel alloy, and the joint portion 55 that hermetically joins the sheath of the sheath thermocouple 50 and the sealing member 51 is formed by welding or brazing. It is not necessary to use any organic material such as, and corrosion of the temperature measuring device 5 due to the processing gas can be prevented to avoid organic contamination.

  When the decompression mechanism 3 decompresses the chamber 1, the process gas supply mechanism 2 supplies the process gas into the chamber 1, and the wafer 40 is heated by the heater 40 for a predetermined time. The supply of the processing gas into the chamber 1 by the processing gas supply mechanism 2 and the heating of the wafer W by the heater 40 are stopped, the loading / unloading port 13 is opened by the gate valve 14, and the wafer W is moved out of the chamber 1 from the loading / unloading port 13. Take it out.

  The present invention is not limited to the above embodiment, and various modifications can be made. In the above embodiment, the temperature measuring device 5 is arranged so that the sheath thermocouple 50 is exposed in the chamber 1. However, as shown in FIG. 4, for example, the sheath thermocouple 50 is accommodated in the cylindrical column member 11. The temperature measuring device 5 may be arranged in the area.

  Moreover, in the said embodiment, it forms integrally from the buffer accommodating part 51c which accommodates the buffer part 50b, the cylinder part 51b which accommodates the compression coil spring 53 and the piston 54, and the flange 51a which protrudes from the one end part of the cylinder part 51b. The sealing member 51 is configured, and this sealing member 51 is attached to the outer surface of the bottom wall 19 of the chamber 1 so that one end surface of the flange 51a is in close contact. For example, as shown in FIG. The outer member 51d attached to the outer surface (bottom surface) of the bottom wall 19 and the inner member 51e attached to the inner surface (upper surface) of the bottom wall 19 of the chamber 1 are configured, and the outer member 51d and the inner member 51e are formed. The shock absorber 50b, the compression coil spring 53, and the piston 54 may be arranged between them. In this case, for example, the outer member 51d is formed in a container shape that accommodates the buffer portion 50b, and the inner member 51e is formed in a ring shape surrounding the sheath thermocouple 50, and the compression coil spring 53 and the piston 54 are formed. Can be arranged in the bottom wall 19 of the chamber 1 so as to be sandwiched between the outer member 51d and the inner member 51e. In this case, the portion surrounding the compression coil spring 53 and the piston 54 on the bottom wall 19 of the chamber 1 also functions as a part of the sealing member 51. With such a configuration, the sealing member 51 (the portion of the sealing member 51 protruding from the bottom wall 19 of the chamber 1) can be reduced in size. The compression coil spring 53 and the piston 54 may be arranged so as to be sandwiched between the outer member and the bottom wall 19 of the chamber 1 without using the inner member, or without using the outer member. The inner member may be formed in a container shape, and the buffer portion 50b, the compression coil spring 53, and the piston 54 may be accommodated in the inner member.

  Moreover, in the said embodiment, although the compression coil spring was used as a spring member, you may use other springs, such as not only this but a tension coil spring.

  Furthermore, in the above-described embodiment, the application example in the case of adjusting the temperature of the semiconductor wafer by heating the heater has been described. However, the present invention is not limited to this, and for example, the present invention is applied to the case of adjusting the wafer temperature by cooling the cooling plate. be able to. Further, the object to be processed is not limited to a semiconductor wafer, but may be a glass substrate for FPD.

  The present invention is disposed in a container having a corrosive gas atmosphere, such as a CVD (Chemical Vapor Deposition) apparatus for performing a film forming process on a semiconductor substrate or a post-heat apparatus for performing a heat treatment on a semiconductor substrate after COR (Chemical Oxide Removal) process. The present invention can be applied to all purposes of measuring the temperature of a temperature sensing object such as a susceptor.

It is sectional drawing which shows schematically the wafer processing apparatus provided with the temperature measuring device as one Embodiment which concerns on this invention. It is sectional drawing of a temperature measuring device. It is a figure which shows the modification of the buffer part provided in the temperature measuring device. It is a figure which shows another attachment aspect to the processing container of a temperature measuring device. It is a figure which shows the modification of the sealing member provided in the temperature measuring device. It is a figure which shows the attachment aspect to the processing container of the conventional sheathed thermocouple.

Explanation of symbols

1: Chamber (container: processing container)
2: Processing gas supply mechanism 4: Susceptor (temperature object)
5: Temperature measuring device 19: Bottom wall (wall)
40: Heater 50: Sheath thermocouple 50a: Tip portion 50b: Buffer portion 51: Sealing member 53: Compression coil spring (spring member)
54: Piston 55: Joining part 90: Controller (control part)

Claims (8)

A temperature measuring device for measuring the temperature of a temperature-measured body arranged in a container,
It has a structure in which a thermocouple wire is covered with a sheath, and is provided so as to extend to the outside of the container, and a tip portion that is located in the container and is movable following the temperature-measured body, A sheathed thermocouple having a buffer part that allows movement of the tip part;
A spring member that biases the distal end portion of the sheath thermocouple in a direction in which the distal end portion is pressed against the temperature measurement object;
A sealing member that houses the spring member and the buffer portion, is provided in close contact with the wall portion of the container so that the inside thereof communicates with the interior of the container, and the terminal portion of the buffer portion extends to the outside. When,
A temperature measuring device comprising: a joint portion formed hermetically by welding or brazing at a portion where the end portion of the buffer portion of the sealing member extends to the outside. A temperature measuring device for measuring the temperature of a temperature measuring object arranged in a corrosive gas atmosphere container,
Having a structure in which a thermocouple wire is covered with a sheath made of a material having corrosion resistance against the corrosive gas, and positioned at the inside of the container and movable in accordance with the measured object; and A sheathed thermocouple provided to extend out of the container and having a buffer portion that allows movement of the tip portion;
A spring member made of a material having corrosion resistance against the corrosive gas, which urges the distal end portion of the sheath thermocouple in a direction in which the distal end portion is pressed against the temperature object;
The spring member and the buffer portion are accommodated, the inner portion thereof is provided in close contact with the wall portion of the container so as to communicate with the interior of the container, and the terminal portion of the buffer portion extends to the outside. A sealing member made of a material having corrosion resistance against corrosive gas;
A temperature measuring device comprising: a joint portion formed hermetically by welding or brazing at a portion where the end portion of the buffer portion of the sealing member extends to the outside. The spring member is a coil spring;
The sealing member accommodates a piston made of a material having corrosion resistance against the corrosive gas, which moves in the advancing and retracting direction with respect to the temperature-measured body as the coil spring expands and contracts.
The temperature measuring device according to claim 2, wherein the sheath thermocouple is fixed to the piston. The corrosive gas is a gas containing halogen,
The temperature measuring device according to claim 2 or 3, wherein the material having corrosion resistance to the corrosive gas is nickel (Ni) or a nickel alloy.   The temperature measuring device according to claim 1, wherein the spring member is made of Inconel (registered trademark).   6. The temperature measuring device according to claim 1, wherein the buffer portion is bent so as to be extendable and retractable in an advancing and retreating direction with respect to the temperature measuring object.   The temperature measuring device according to claim 6, wherein the buffer portion is bent in a spiral shape.   The temperature measuring device according to claim 6, wherein the buffer portion is bent in a waveform.

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